Tofu is one of the most multi-purpose grocery items out there. It’s a handy stir-fry ingredient, and an inspiration for many an intriguing dish. In addition, there’s a tofu-based substitute for practically any food you could name. What you may not have guessed, though, is that, because it is made by coagulating soy milk (which makes it, one supposes, sort of the soy equivalent of cheese), it is also highly perishable and should be stored with care, particularly after opening.

You can buy tofu either refrigerated or unrefrigerated (in aseptic packaging). Reportedly, the aseptic version is not as good.

You will probably notice one brand dominating the refrigerated tofu section, if not completely monopolizing it. That would be the House Foods brand, which comes in several varieties of firmness. Printed at the bottom of the front label is an expiration date; on our most recent grocery run, we found the expiration dates to be anywhere from 3 to 7 weeks away. House Foods is very adamant about its expiration dates, intoning on its FAQ page, "We do not assure the freshness of expired products." So okay, checking the date is key.

And once it's opened? Whether it came from the store’s fridge or open shelves, Hurry up and eat it, is the going advice, or more specifically: "If the Tofu is within the code date, it will last approximately 2-3 days in the refrigerator." House Foods adds, "Our Tofu is pasteurized, somewhat like milk, so it might last shorter or longer depending on the condition and the code date of the Tofu." Fortunately, your average tofu product contains 12-14 ounces, so a few days to consume that is certainly doable. However, even if that amount happens to outsize your appetite for the stuff, it's a relatively small investment to write off, so when in doubt, toss.

What you'll also notice after opening your tofu is that it is packaged in water. That’s because "the water helps it maintain its bulk and form. Tofu sold this way has a fresher taste and better consistency than Tofu that has been packed without water in aseptic packaging." House Foods also advises that any tofu you wish to preserve after opening the package should be kept in an air-tight container, and that "Water should be added to the container in order for the Tofu to keep its moisture."

Keep in mind that the "2-3 days" advice comes from tofu manufacturers themselves, who lean toward estimates on the conservative side. The advisers at Wikihow give a more liberal estimate of 7-10 days, provided you follow the site’s explicit instructions, which include a) filling a container with enough water (new water, mind you, not the water the tofu was packaged in); and b ) changing the water daily (or at least every second day). This, the site admits, is a bit of "a chore but it is important to keep the tofu in top condition." All other sources we checked confirm the "daily water change" ritual, so this is clearly not just a case of Wikihow being obsessive-compulsive.

There is also pretty much web-wide consensus on the results of freezing tofu, best exemplified by this Amazon Askville answer: "You can freeze tofu for up to 3 months. Drain the water from the opened tofu package. Put into an airtight container and freeze. The taste will be the same, but the texture will be a little firmer." Indeed, House Foods actively discourages freezing it but concedes, "However, if you would like the Tofu to adopt a chewy, meat-like texture, freezing is an option. Do not be surprised if the Tofu comes out of the freezer with a completely different texture!"

Tofu is a handy and healthy choice for those who are vegetarian, lactose-intolerant, or otherwise allergic to dairy. It’s an affordable, easy-to-prepare source of protein and calcium. What it lacks in durability it makes up for in versatility, so if you'd rather not go to the effort it takes to properly store it once opened, you have no shortage of other options.

Store opened tofu in an airtight container. Cover the tofu with water for two reasons: 1) it keeps the product moist; and 2) it keeps highly absorbent tofu from absorbing odors and flavors from other foods in your fridge.

If your refrigerated tofu looks yellow or smells bad, discard it. Fresh tofu does not have any scent.